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Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf
[linux/fpc-iii.git] / drivers / i2c / busses / i2c-hix5hd2.c
blob7c6966434ee7b9a2707da849e56128af41c0baf5
1 /*
2 * Copyright (c) 2014 Linaro Ltd.
3 * Copyright (c) 2014 Hisilicon Limited.
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * Now only support 7 bit address.
11 */
12
13 #include <linux/clk.h>
14 #include <linux/delay.h>
15 #include <linux/i2c.h>
16 #include <linux/io.h>
17 #include <linux/interrupt.h>
18 #include <linux/module.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/pm_runtime.h>
22
23 /* Register Map */
24 #define HIX5I2C_CTRL 0x00
25 #define HIX5I2C_COM 0x04
26 #define HIX5I2C_ICR 0x08
27 #define HIX5I2C_SR 0x0c
28 #define HIX5I2C_SCL_H 0x10
29 #define HIX5I2C_SCL_L 0x14
30 #define HIX5I2C_TXR 0x18
31 #define HIX5I2C_RXR 0x1c
32
33 /* I2C_CTRL_REG */
34 #define I2C_ENABLE BIT(8)
35 #define I2C_UNMASK_TOTAL BIT(7)
36 #define I2C_UNMASK_START BIT(6)
37 #define I2C_UNMASK_END BIT(5)
38 #define I2C_UNMASK_SEND BIT(4)
39 #define I2C_UNMASK_RECEIVE BIT(3)
40 #define I2C_UNMASK_ACK BIT(2)
41 #define I2C_UNMASK_ARBITRATE BIT(1)
42 #define I2C_UNMASK_OVER BIT(0)
43 #define I2C_UNMASK_ALL (I2C_UNMASK_ACK | I2C_UNMASK_OVER)
44
45 /* I2C_COM_REG */
46 #define I2C_NO_ACK BIT(4)
47 #define I2C_START BIT(3)
48 #define I2C_READ BIT(2)
49 #define I2C_WRITE BIT(1)
50 #define I2C_STOP BIT(0)
51
52 /* I2C_ICR_REG */
53 #define I2C_CLEAR_START BIT(6)
54 #define I2C_CLEAR_END BIT(5)
55 #define I2C_CLEAR_SEND BIT(4)
56 #define I2C_CLEAR_RECEIVE BIT(3)
57 #define I2C_CLEAR_ACK BIT(2)
58 #define I2C_CLEAR_ARBITRATE BIT(1)
59 #define I2C_CLEAR_OVER BIT(0)
60 #define I2C_CLEAR_ALL (I2C_CLEAR_START | I2C_CLEAR_END | \
61 I2C_CLEAR_SEND | I2C_CLEAR_RECEIVE | \
62 I2C_CLEAR_ACK | I2C_CLEAR_ARBITRATE | \
63 I2C_CLEAR_OVER)
64
65 /* I2C_SR_REG */
66 #define I2C_BUSY BIT(7)
67 #define I2C_START_INTR BIT(6)
68 #define I2C_END_INTR BIT(5)
69 #define I2C_SEND_INTR BIT(4)
70 #define I2C_RECEIVE_INTR BIT(3)
71 #define I2C_ACK_INTR BIT(2)
72 #define I2C_ARBITRATE_INTR BIT(1)
73 #define I2C_OVER_INTR BIT(0)
74
75 #define HIX5I2C_MAX_FREQ 400000 /* 400k */
76 #define HIX5I2C_READ_OPERATION 0x01
77
78 enum hix5hd2_i2c_state {
79 HIX5I2C_STAT_RW_ERR = -1,
80 HIX5I2C_STAT_INIT,
81 HIX5I2C_STAT_RW,
82 HIX5I2C_STAT_SND_STOP,
83 HIX5I2C_STAT_RW_SUCCESS,
84 };
85
86 struct hix5hd2_i2c_priv {
87 struct i2c_adapter adap;
88 struct i2c_msg *msg;
89 struct completion msg_complete;
90 unsigned int msg_idx;
91 unsigned int msg_len;
92 int stop;
93 void __iomem *regs;
94 struct clk *clk;
95 struct device *dev;
96 spinlock_t lock; /* IRQ synchronization */
97 int err;
98 unsigned int freq;
99 enum hix5hd2_i2c_state state;
100 };
101
102 static u32 hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv *priv)
103 {
104 u32 val = readl_relaxed(priv->regs + HIX5I2C_SR);
105
106 writel_relaxed(val, priv->regs + HIX5I2C_ICR);
107
108 return val;
109 }
110
111 static void hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv *priv)
112 {
113 writel_relaxed(I2C_CLEAR_ALL, priv->regs + HIX5I2C_ICR);
114 }
115
116 static void hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv *priv)
117 {
118 writel_relaxed(0, priv->regs + HIX5I2C_CTRL);
119 }
120
121 static void hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv *priv)
122 {
123 writel_relaxed(I2C_ENABLE | I2C_UNMASK_TOTAL | I2C_UNMASK_ALL,
124 priv->regs + HIX5I2C_CTRL);
125 }
126
127 static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv *priv)
128 {
129 u32 rate, val;
130 u32 scl, sysclock;
131
132 /* close all i2c interrupt */
133 val = readl_relaxed(priv->regs + HIX5I2C_CTRL);
134 writel_relaxed(val & (~I2C_UNMASK_TOTAL), priv->regs + HIX5I2C_CTRL);
135
136 rate = priv->freq;
137 sysclock = clk_get_rate(priv->clk);
138 scl = (sysclock / (rate * 2)) / 2 - 1;
139 writel_relaxed(scl, priv->regs + HIX5I2C_SCL_H);
140 writel_relaxed(scl, priv->regs + HIX5I2C_SCL_L);
141
142 /* restore original interrupt*/
143 writel_relaxed(val, priv->regs + HIX5I2C_CTRL);
144
145 dev_dbg(priv->dev, "%s: sysclock=%d, rate=%d, scl=%d\n",
146 __func__, sysclock, rate, scl);
147 }
148
149 static void hix5hd2_i2c_init(struct hix5hd2_i2c_priv *priv)
150 {
151 hix5hd2_i2c_disable_irq(priv);
152 hix5hd2_i2c_drv_setrate(priv);
153 hix5hd2_i2c_clr_all_irq(priv);
154 hix5hd2_i2c_enable_irq(priv);
155 }
156
157 static void hix5hd2_i2c_reset(struct hix5hd2_i2c_priv *priv)
158 {
159 clk_disable_unprepare(priv->clk);
160 msleep(20);
161 clk_prepare_enable(priv->clk);
162 hix5hd2_i2c_init(priv);
163 }
164
165 static int hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv *priv)
166 {
167 unsigned long stop_time;
168 u32 int_status;
169
170 /* wait for 100 milli seconds for the bus to be idle */
171 stop_time = jiffies + msecs_to_jiffies(100);
172 do {
173 int_status = hix5hd2_i2c_clr_pend_irq(priv);
174 if (!(int_status & I2C_BUSY))
175 return 0;
176
177 usleep_range(50, 200);
178 } while (time_before(jiffies, stop_time));
179
180 return -EBUSY;
181 }
182
183 static void hix5hd2_rw_over(struct hix5hd2_i2c_priv *priv)
184 {
185 if (priv->state == HIX5I2C_STAT_SND_STOP)
186 dev_dbg(priv->dev, "%s: rw and send stop over\n", __func__);
187 else
188 dev_dbg(priv->dev, "%s: have not data to send\n", __func__);
189
190 priv->state = HIX5I2C_STAT_RW_SUCCESS;
191 priv->err = 0;
192 }
193
194 static void hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv *priv)
195 {
196 if (priv->stop) {
197 priv->state = HIX5I2C_STAT_SND_STOP;
198 writel_relaxed(I2C_STOP, priv->regs + HIX5I2C_COM);
199 } else {
200 hix5hd2_rw_over(priv);
201 }
202 }
203
204 static void hix5hd2_read_handle(struct hix5hd2_i2c_priv *priv)
205 {
206 if (priv->msg_len == 1) {
207 /* the last byte don't need send ACK */
208 writel_relaxed(I2C_READ | I2C_NO_ACK, priv->regs + HIX5I2C_COM);
209 } else if (priv->msg_len > 1) {
210 /* if i2c master receive data will send ACK */
211 writel_relaxed(I2C_READ, priv->regs + HIX5I2C_COM);
212 } else {
213 hix5hd2_rw_handle_stop(priv);
214 }
215 }
216
217 static void hix5hd2_write_handle(struct hix5hd2_i2c_priv *priv)
218 {
219 u8 data;
220
221 if (priv->msg_len > 0) {
222 data = priv->msg->buf[priv->msg_idx++];
223 writel_relaxed(data, priv->regs + HIX5I2C_TXR);
224 writel_relaxed(I2C_WRITE, priv->regs + HIX5I2C_COM);
225 } else {
226 hix5hd2_rw_handle_stop(priv);
227 }
228 }
229
230 static int hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv *priv)
231 {
232 u8 data;
233
234 if (priv->state == HIX5I2C_STAT_INIT) {
235 priv->state = HIX5I2C_STAT_RW;
236 } else if (priv->state == HIX5I2C_STAT_RW) {
237 if (priv->msg->flags & I2C_M_RD) {
238 data = readl_relaxed(priv->regs + HIX5I2C_RXR);
239 priv->msg->buf[priv->msg_idx++] = data;
240 }
241 priv->msg_len--;
242 } else {
243 dev_dbg(priv->dev, "%s: error: priv->state = %d, msg_len = %d\n",
244 __func__, priv->state, priv->msg_len);
245 return -EAGAIN;
246 }
247 return 0;
248 }
249
250 static irqreturn_t hix5hd2_i2c_irq(int irqno, void *dev_id)
251 {
252 struct hix5hd2_i2c_priv *priv = dev_id;
253 u32 int_status;
254 int ret;
255
256 spin_lock(&priv->lock);
257
258 int_status = hix5hd2_i2c_clr_pend_irq(priv);
259
260 /* handle error */
261 if (int_status & I2C_ARBITRATE_INTR) {
262 /* bus error */
263 dev_dbg(priv->dev, "ARB bus loss\n");
264 priv->err = -EAGAIN;
265 priv->state = HIX5I2C_STAT_RW_ERR;
266 goto stop;
267 } else if (int_status & I2C_ACK_INTR) {
268 /* ack error */
269 dev_dbg(priv->dev, "No ACK from device\n");
270 priv->err = -ENXIO;
271 priv->state = HIX5I2C_STAT_RW_ERR;
272 goto stop;
273 }
274
275 if (int_status & I2C_OVER_INTR) {
276 if (priv->msg_len > 0) {
277 ret = hix5hd2_rw_preprocess(priv);
278 if (ret) {
279 priv->err = ret;
280 priv->state = HIX5I2C_STAT_RW_ERR;
281 goto stop;
282 }
283 if (priv->msg->flags & I2C_M_RD)
284 hix5hd2_read_handle(priv);
285 else
286 hix5hd2_write_handle(priv);
287 } else {
288 hix5hd2_rw_over(priv);
289 }
290 }
291
292 stop:
293 if ((priv->state == HIX5I2C_STAT_RW_SUCCESS &&
294 priv->msg->len == priv->msg_idx) ||
295 (priv->state == HIX5I2C_STAT_RW_ERR)) {
296 hix5hd2_i2c_disable_irq(priv);
297 hix5hd2_i2c_clr_pend_irq(priv);
298 complete(&priv->msg_complete);
299 }
300
301 spin_unlock(&priv->lock);
302
303 return IRQ_HANDLED;
304 }
305
306 static void hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv *priv, int stop)
307 {
308 unsigned long flags;
309
310 spin_lock_irqsave(&priv->lock, flags);
311 hix5hd2_i2c_clr_all_irq(priv);
312 hix5hd2_i2c_enable_irq(priv);
313
314 if (priv->msg->flags & I2C_M_RD)
315 writel_relaxed((priv->msg->addr << 1) | HIX5I2C_READ_OPERATION,
316 priv->regs + HIX5I2C_TXR);
317 else
318 writel_relaxed(priv->msg->addr << 1,
319 priv->regs + HIX5I2C_TXR);
320
321 writel_relaxed(I2C_WRITE | I2C_START, priv->regs + HIX5I2C_COM);
322 spin_unlock_irqrestore(&priv->lock, flags);
323 }
324
325 static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv,
326 struct i2c_msg *msgs, int stop)
327 {
328 unsigned long timeout;
329 int ret;
330
331 priv->msg = msgs;
332 priv->msg_idx = 0;
333 priv->msg_len = priv->msg->len;
334 priv->stop = stop;
335 priv->err = 0;
336 priv->state = HIX5I2C_STAT_INIT;
337
338 reinit_completion(&priv->msg_complete);
339 hix5hd2_i2c_message_start(priv, stop);
340
341 timeout = wait_for_completion_timeout(&priv->msg_complete,
342 priv->adap.timeout);
343 if (timeout == 0) {
344 priv->state = HIX5I2C_STAT_RW_ERR;
345 priv->err = -ETIMEDOUT;
346 dev_warn(priv->dev, "%s timeout=%d\n",
347 msgs->flags & I2C_M_RD ? "rx" : "tx",
348 priv->adap.timeout);
349 }
350 ret = priv->state;
351
352 /*
353 * If this is the last message to be transfered (stop == 1)
354 * Then check if the bus can be brought back to idle.
355 */
356 if (priv->state == HIX5I2C_STAT_RW_SUCCESS && stop)
357 ret = hix5hd2_i2c_wait_bus_idle(priv);
358
359 if (ret < 0)
360 hix5hd2_i2c_reset(priv);
361
362 return priv->err;
363 }
364
365 static int hix5hd2_i2c_xfer(struct i2c_adapter *adap,
366 struct i2c_msg *msgs, int num)
367 {
368 struct hix5hd2_i2c_priv *priv = i2c_get_adapdata(adap);
369 int i, ret, stop;
370
371 pm_runtime_get_sync(priv->dev);
372
373 for (i = 0; i < num; i++, msgs++) {
374 stop = (i == num - 1);
375 ret = hix5hd2_i2c_xfer_msg(priv, msgs, stop);
376 if (ret < 0)
377 goto out;
378 }
379
380 if (i == num) {
381 ret = num;
382 } else {
383 /* Only one message, cannot access the device */
384 if (i == 1)
385 ret = -EREMOTEIO;
386 else
387 ret = i;
388
389 dev_warn(priv->dev, "xfer message failed\n");
390 }
391
392 out:
393 pm_runtime_mark_last_busy(priv->dev);
394 pm_runtime_put_autosuspend(priv->dev);
395 return ret;
396 }
397
398 static u32 hix5hd2_i2c_func(struct i2c_adapter *adap)
399 {
400 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
401 }
402
403 static const struct i2c_algorithm hix5hd2_i2c_algorithm = {
404 .master_xfer = hix5hd2_i2c_xfer,
405 .functionality = hix5hd2_i2c_func,
406 };
407
408 static int hix5hd2_i2c_probe(struct platform_device *pdev)
409 {
410 struct device_node *np = pdev->dev.of_node;
411 struct hix5hd2_i2c_priv *priv;
412 struct resource *mem;
413 unsigned int freq;
414 int irq, ret;
415
416 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
417 if (!priv)
418 return -ENOMEM;
419
420 if (of_property_read_u32(np, "clock-frequency", &freq)) {
421 /* use 100k as default value */
422 priv->freq = 100000;
423 } else {
424 if (freq > HIX5I2C_MAX_FREQ) {
425 priv->freq = HIX5I2C_MAX_FREQ;
426 dev_warn(priv->dev, "use max freq %d instead\n",
427 HIX5I2C_MAX_FREQ);
428 } else {
429 priv->freq = freq;
430 }
431 }
432
433 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
434 priv->regs = devm_ioremap_resource(&pdev->dev, mem);
435 if (IS_ERR(priv->regs))
436 return PTR_ERR(priv->regs);
437
438 irq = platform_get_irq(pdev, 0);
439 if (irq <= 0) {
440 dev_err(&pdev->dev, "cannot find HS-I2C IRQ\n");
441 return irq;
442 }
443
444 priv->clk = devm_clk_get(&pdev->dev, NULL);
445 if (IS_ERR(priv->clk)) {
446 dev_err(&pdev->dev, "cannot get clock\n");
447 return PTR_ERR(priv->clk);
448 }
449 clk_prepare_enable(priv->clk);
450
451 strlcpy(priv->adap.name, "hix5hd2-i2c", sizeof(priv->adap.name));
452 priv->dev = &pdev->dev;
453 priv->adap.owner = THIS_MODULE;
454 priv->adap.algo = &hix5hd2_i2c_algorithm;
455 priv->adap.retries = 3;
456 priv->adap.dev.of_node = np;
457 priv->adap.algo_data = priv;
458 priv->adap.dev.parent = &pdev->dev;
459 i2c_set_adapdata(&priv->adap, priv);
460 platform_set_drvdata(pdev, priv);
461 spin_lock_init(&priv->lock);
462 init_completion(&priv->msg_complete);
463
464 hix5hd2_i2c_init(priv);
465
466 ret = devm_request_irq(&pdev->dev, irq, hix5hd2_i2c_irq,
467 IRQF_NO_SUSPEND | IRQF_ONESHOT,
468 dev_name(&pdev->dev), priv);
469 if (ret != 0) {
470 dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", irq);
471 goto err_clk;
472 }
473
474 pm_suspend_ignore_children(&pdev->dev, true);
475 pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC);
476 pm_runtime_use_autosuspend(priv->dev);
477 pm_runtime_set_active(priv->dev);
478 pm_runtime_enable(priv->dev);
479
480 ret = i2c_add_adapter(&priv->adap);
481 if (ret < 0) {
482 dev_err(&pdev->dev, "failed to add bus to i2c core\n");
483 goto err_runtime;
484 }
485
486 return ret;
487
488 err_runtime:
489 pm_runtime_disable(priv->dev);
490 pm_runtime_set_suspended(priv->dev);
491 err_clk:
492 clk_disable_unprepare(priv->clk);
493 return ret;
494 }
495
496 static int hix5hd2_i2c_remove(struct platform_device *pdev)
497 {
498 struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
499
500 i2c_del_adapter(&priv->adap);
501 pm_runtime_disable(priv->dev);
502 pm_runtime_set_suspended(priv->dev);
503
504 return 0;
505 }
506
507 #ifdef CONFIG_PM
508 static int hix5hd2_i2c_runtime_suspend(struct device *dev)
509 {
510 struct platform_device *pdev = to_platform_device(dev);
511 struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
512
513 clk_disable_unprepare(priv->clk);
514
515 return 0;
516 }
517
518 static int hix5hd2_i2c_runtime_resume(struct device *dev)
519 {
520 struct platform_device *pdev = to_platform_device(dev);
521 struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
522
523 clk_prepare_enable(priv->clk);
524 hix5hd2_i2c_init(priv);
525
526 return 0;
527 }
528 #endif
529
530 static const struct dev_pm_ops hix5hd2_i2c_pm_ops = {
531 SET_RUNTIME_PM_OPS(hix5hd2_i2c_runtime_suspend,
532 hix5hd2_i2c_runtime_resume,
533 NULL)
534 };
535
536 static const struct of_device_id hix5hd2_i2c_match[] = {
537 { .compatible = "hisilicon,hix5hd2-i2c" },
538 {},
539 };
540 MODULE_DEVICE_TABLE(of, hix5hd2_i2c_match);
541
542 static struct platform_driver hix5hd2_i2c_driver = {
543 .probe = hix5hd2_i2c_probe,
544 .remove = hix5hd2_i2c_remove,
545 .driver = {
546 .name = "hix5hd2-i2c",
547 .pm = &hix5hd2_i2c_pm_ops,
548 .of_match_table = hix5hd2_i2c_match,
549 },
550 };
551
552 module_platform_driver(hix5hd2_i2c_driver);
553
554 MODULE_DESCRIPTION("Hix5hd2 I2C Bus driver");
555 MODULE_AUTHOR("Wei Yan <sledge.yanwei@huawei.com>");
556 MODULE_LICENSE("GPL");
557 MODULE_ALIAS("platform:hix5hd2-i2c");
Linux with added FPC-III support